An RBC is typically comprised of a rotating shaft to which is attached a bank, or multiple banks, of media that are then in turn rotated by the shaft. A plurality of parallel support shafts is typically employed to aid in the support of the media. The media is typically located such that about 40 percent of the media is, at any given time, immersed in the wastewater to be cleaned. As the media rotates slowly into and out of the wastewater, microorganisms attach themselves to the media, forming a biomass, and consuming contaminants from the wastewater. As the media rotates into the air above the wastewater tank, the microorganisms biodegrade these contaminants, e.g., into carbon dioxide and water.
Examples of technology related to the treatment of wastewater and other substances can be found with reference to the following U.S. patents listed in the Table, below, the entire disclosures of which are expressly incorporated herein by reference:
TABLEU.S. Pat. No.Inventor(s)Title1,811,181MaltbyProcess and Apparatus forTreating Sewage or OtherOrganic Matters1,947,777Huff et al.Filling Unit3,193,989SebesteAerating Waste TreatmentApparatus3,335,081El-NaggarMethod of Treatment ofSewage by Bio-Oxidationand Apparatus Therefor3,484,836WelchRotating BiologicalContactor in Sewer3,630,366JoostRotating Biological WasteTreatment System3,645,510KlugmanGrid Member and WallFormed Therefrom3,704,783AntoineApparatus for TreatingSewage3,904,525Rosenberg et al.Waste Treatment Apparatus3,915,854TorpeyWastewater Treatment4,115,268ThissenWaste Water TreatmentRotor4,137,172Sako et al.Rotating BiologicalContactor4,275,019BednarskiA Modular Heaping-TypePacking Element4,279,753Nielson et al.Wastewater TreatmentSystem Including MultipleStages of AlternateAerobic-AnaerobicBioreactors in Series4,303,527Reimann et al.Surge Control in theBiological Purification ofWastewater4,345,997McConnell, Jr. et al.Media4,385,987McGinley et al.Waste Treatment Apparatus4,387,020HillFlow Control Apparatus4,399,031Imano et al.Biological SewageTreatment Apparatus of theRotary Disc Type4,431,537HirotaRevolving Contactors forthe Biological Treatment ofWaste Water4,444,658Hankes et al.Rotating BiologicalContactor Apparatus4,468,326KawertProcess in MicrobiologicalPurification and a Deviceand Materials Therefor4,532,038ReidFlow Control Apparatus forAerobic Sewage Treatment4,537,678ThissenRotary Biological Contactor4,549,962KoelschRotating BiologicalContactor4,608,162Hankes et al.Rotating BiologicalContactor Apparatus4,692,241NicholsonSewage TreatmentBiological Rotors4,724,593LangMethod and Blank for theManufacture of HighEfficiency Open VolumedPacking Bodies4,737,278MillerMiniturized ModularRotating BiologicalContactor System4,999,302Kahler et al.Biological Contact GasScrubber for Waste GasPurification5,407,578NathwaniWaste Water TreatmentProcess5,419,831Fuerst et al.Rotating BiologicalAquarium Filter System5,423,978Snyder et al.Rotating BiologicAquarium Filter System5,425,874GassRotating ContactorIncluding Cross FlowMedia for the BiologicalTreatment of Waste Water5,458,817LangFolding Packing andMethod of Manufacture5,498,376St. Louis et al.Packing5,637,263Lang et al.Multifold Packing andMethod of Forming5,679,253Fuerst et al.Rotating BiologicalAquarium Filter System5,714,097St. Louis et al.Packing5,851,636Lang et al.Ceramic Packing WithChannels for Thermal andCatalytic Beds5,853,591Snyder et al.Rotating BiologicalAquarium Filter System6,071,593Lang et al.Ceramic Packing WithChannels for Thermal andCatalytic Beds6,241,222LangStacked Packing WithSpacing Features6,403,366KimMethod and Apparatus forTreating Volatile OrganicCompounds, Odors, andBiodegradable in AirEmissions6,540,920Bounds et al.Wastewater TreatmentSystem Utilizing TextileFilter Media6,783,669Okagawa et al.Rotating Disk Type SewageTreatment Device
The microorganisms in typical wastewater normally form a biomass on the media that is about 0.03 inches thick. When the system becomes overloaded, the biomass will typically grow to a thickness of about 0.15 inches. When this occurs, the microorganisms that were the first to attach to the media die because no food or oxygen can get to them. When this occurs over a large enough area, the biomass detaches itself from the media and sloughs off.
Conventional media is typically comprised of planar surfaces that are either flat or folded and are either made of a mesh or a solid sheet. Both the flat and the folded types of media are spaced to provide a path that allows the sloughed biomass (i.e., biomass that has become detached from the media) to be washed out of the media. This is needed to prevent plugging of the system which would reduce the media surface area exposed to contaminants in the wastewater and thus reduce the capacity of the system.
The mesh media, which by its nature must be flat, is also typically very flimsy. Because the mesh is a single flat disk, typically spaced from one another, in order to allow the sloughed biomass to be washed out of the media, the area exposed is typically limited to only about 32 square feet per cubic foot. Also, because the mesh is flimsy, the adjacent disks must be separated by many spacers or one disk will flop against the adjacent disk, reducing the surface area exposed.
One solution to this problem is described in U.S. Patent Publication No. 20050133444, published Jun. 23, 2005, corresponding to U.S. patent application Ser. No. 10/997,117, filed Nov. 24, 2004, the entire specification of which is expressly incorporated herein by reference. The patent application describes a self-cleansing media and systems incorporating the same, for a rotating biological contactor. The media includes a disk having cones extending perpendicularly from the surface thereof. Two or more disks lock together, axially about a rotating central shaft, by connecting cones spaced throughout the disk surface having a socket at their base to receive the top of the corresponding connecting cone on the adjacent disk. The cones, by virtue of their length, space the disks a desired distance. The disks include disk segments that can link to one another along either straight and/or curved portions thereof. The geometry of the media provides free passage of the air and water during each revolution, and while the base disk slices through the air and water, the projecting cones or cylinders enter the air and water perpendicular to the direction of rotation and are washed and cleansed during each rotation. However, because there are projections on only one side of the disks, it is difficult to form the disks with conventional molding techniques.
Therefore, there exists a need for new and improved media, and systems incorporating the same, for use in conjunction with rotating biological contactors and the like.